Rebar Estimator
Bar count, cutting length and steel weight
Reinforcement layout
Estimate only — laps, bends and detailing follow your drawings and local code.
Estimated steel
Bar mass reference
Nominal mass per metre for deformed bars.
| Bar | Mass |
|---|---|
| Ø8 mm Bar | – |
| Ø10 mm Bar | – |
| Ø12 mm Bar | – |
| Ø16 mm Bar | – |
| Ø20 mm Bar | – |
| Ø25 mm Bar | – |
| Ø32 mm Bar | – |
About Rebar Estimator
The rebar estimator counts the reinforcing bars in a slab or mat and converts them into total length and steel weight. Enter the slab’s length and width, the bar spacing in millimeters, and the bar size; toggle two-way mesh to run bars in both directions, and add a percentage for laps and wastage.
The weight comes from the standard formula for round steel: mass per meter = d² × 0.006165, where d is the bar diameter in millimeters — so a 12 mm bar weighs about 0.888 kg/m and a 16 mm bar about 1.58 kg/m. A reference table lists the nominal mass for every common size, with your selected bar highlighted.
Use it to price the steel for a slab, footing mat, or driveway before ordering, free in your browser. It is a quantity estimate only: lap lengths, bends, chairs, and detailing follow your structural drawings and local code, which is why the laps-and-wastage percentage exists.
How to use Rebar Estimator
- Enter the slab length and width in meters.
- Set the bar spacing in millimeters — 150 or 200 mm grids are common in slabs.
- Choose the bar size and toggle two-way mesh if bars run in both directions.
- Add a percentage for laps and wastage.
- Read the bar counts per direction, total bar length, and estimated steel weight.